As an alternative to powering vehicles using the internal combustion engine, designers have experimented with batteries, fuel cells, and solar panels.
These experiments have been motivated, in large part, by a concern that gases emitted by internal combustion engines could harm humans by adversely affecting their environment. Motivated by these concerns, lawmakers have passed laws governing vehicle emissions.
Accordingly, there is an ongoing need for sources of power that can supplement or replace the internal combustion engine as a source of power for vehicles.
For similar reasons, there is a need for alternative stationary sources of power, that reduce harmful environmental effects associated with the combustion of fossil fuels.